Understanding How Horses Sleep Standing Up vs Laying Down
- Equine Sleep Patterns and Stages
- How Much Sleep Does My Horse Need?
- Why Do Horses Sleep Standing Up?
- Understanding the Stay Apparatus
- Ensuring Your Horse Gets Quality Sleep Time
- Video on Sleeping Habits for Horses
- Evidence-Based References
Snooze schedules and the stay apparatus.
Updated July 1, 2024
Just like for people, the amount and quality of sleep your horse gets each day is fundamental to their health and well-being. However, horses need far less sleep than humans to function and they may even rest while standing up.
We’ll explain what a normal sleep cycle is for horses, how much shuteye they need per day, and strategies you can use to help your horse get quality sleep.
Equine Sleep Patterns and Stages
While many people need continuous hours of uninterrupted, quality sleep each day, horses can have multiple periods of sleep throughout 24 hours. They are known as polyphasic sleepers who take short naps throughout the day with most of their sleep concentrated at night.
Sleep cycles can be broken down into four stages documented in horses, which include:
- Wakefulness: A full sleep cycle includes periods where the horse is awakened.
- Drowsiness or Light Sleep: Typically occurs just before NREM or REM sleep.
- Non-Rapid Eye Movement (NREM): Also known as slow wave sleep, this is a state of deep rest where a horse’s brain waves significantly slow down. Horses can enter NREM sleep while standing up or lying down in sternal recumbency (with their legs tucked underneath them, but not fully flat out).
- Rapid Eye Movement (REM): Characterized by quick, irregular brain waves that are similar to when a horse is awake, along with rapid back-and-forth eye movements. REM sleep can only take place when a horse is lying down on their side. Even though all their muscles become completely relaxed during this stage, you may see some twitches in the ears, skin, nostrils, eyelids, and legs.
How Much Sleep Does My Horse Need?
Adult horses generally need 5-7 hours of sleep per day. Most of this (over 75%) can be NREM sleep while standing up. However, horses need about 30 minutes of that time to be REM sleep which can only happen while lying down.
This relatively short amount of REM sleep is required every day. If your horse doesn’t have this, they may become sleep deprived, narcoleptic, or suffer other health consequences. Some horses are able to delay when they get REM sleep for several days without serious health effects, however, classic signs of sleep deprivation (like collapsing) may begin to show.
Why Do Horses Sleep Standing Up?
Horses are prey animals and sleeping standing up is one way in which they’ve adapted to the threat of predators. This survival mechanism allows them to remain somewhat alert and ready to quickly flee from predators without the delay and effort of getting up from the ground. Other equids, like donkeys and zebras, are also able to sleep standing up.
Another reason why horses sleep standing up has to do with their large body size and weight. Lying down for too long can interfere with blood flow and their substantial weight can put stress on internal organs and nerves.
Although, adult horses do sleep lying down, they only do so for short periods (typically less than an hour). Young horses and foals can sleep lying down for longer periods, but they also weigh far less.
Understanding the Stay Apparatus
You may be wondering how horses can get some sleep on all four legs without toppling over. Well, they have a special system of tendons and ligaments that stabilize the major joints in their legs called the stay apparatus. These soft tissues stabilize the joints in the forelimb and hindlimb, allowing horses to doze while standing with little effort.
Ensuring Your Horse Gets Quality Sleep Time
As an owner or caretaker, there are several factors that influence if your horse can snooze in peace.
Environmental Factors
Make sure your horse has enough room to comfortably lie down, whether that be the size of the stall, run in, or paddock. Also consider the quality and comfort of the bedding you’re using. One study showed that horses are more likely to sleep when they have access to a soft, thick bedded and adequately sized area suitable for lying down [2].
Another factor is how familiar your horse is with their surroundings. Many horses require a period to acclimate to a new barn or paddock before feeling safe enough to lie down and sleep.
Lastly, artificial light can affect circadian rhythms. A study examining the effects of overnight light on sleep behavior showed horses spent less time in recumbent sleep (NREM and REM) [3]. So be sure to turn off the lights every night and during the day when not necessary. You may also find success with using specially designed masks that block blue light to help support the natural production of melatonin, and therefore restful sleep.
Herd Mentality
Horses naturally belong in a herd and the absence of that social dynamic can affect their sleep. A herd – whether in the wild, out to pasture, or seeing each other through stall dividers – may have some horses lying down sleeping or resting while one or two others are standing, essentially keeping guard in case there is danger (predators). If your horse is the only equine or animal on the property, they don’t have anyone standing guard for them while sleeping, and this can cause them to be sleep deprived.
Physical Discomfort
Conditions that cause pain, like arthritis or laminitis, may prevent a horse from lying down, due to the potential effort and discomfort of standing back up. Many senior horses with joint discomfort will avoid lying down for this reason, and therefore, become deprived of REM sleep.
In this case, it may be smart to call your veterinarian so they can examine your horse and diagnose any pain or discomfort. They may be able to prescribe medications or discuss other treatments, including supplements, to address the source of discomfort.
More research needs to be done on other potential factors affecting sleep such as the horse’s emotional state, level of exercise, and nutrition.
Video on Sleeping Habits for Horses
In this video, Dr. Lydia Gray describes the requirements for horses to have restful, complete sleep cycles and factors that may hinder this.
DAN: "Horse sleep habits-- are there any unusual patterns that should cause concern, like not laying down enough, sleep position? My pony lays on her back sometimes. I've never seen that before." Neither have I. Please send us a photo.
DR. LYDIA GRAY: I have not seen that either.
DAN: It's very curious about that. "And what can you do to help encourage better sleep habits?"
DR. LYDIA GRAY: Well, I'm going to go back to laying on their back.
DAN: Yeah, that's a great one.
DR. LYDIA GRAY: Foals will lay on their back-- we call it "dorsal recumbency"-- when they have gastric ulcers. That's a very specific clinical sign and a very specific condition. But I've not seen or heard of an adult horse lying on their back.
If that's normal for her horse, like the one we just talked about, fine. But if that's only something that happens when there's a problem--
DAN: So if it's happening here and there--
DR. LYDIA GRAY: Yeah. Yeah. So that's very interesting. Otherwise, back to normal horses' sleeping habits. You've probably heard the whole thing about horses sleep standing up because they have a stay apparatus in their hind legs that let them doze while standing. And the key word there is "doze." Horses can lightly sleep sort of in a half-alert half-asleep manner. But that's not how they get full sleep.
And horses do have to get full sleep-- now, not as much as us. They only need like three to four hours of sleep a day and only 30 minutes of the REM, the Rapid Eye Movement.
DAN: Wow.
DR. LYDIA GRAY: And they can actually go a while-- you know-- maybe you don't know-- I know if you lose sleep, in a day or two-- as quickly as a day or two, you begin to feel the effects of it in your concentration, your focus.
DAN: Oh, I can feel it in one day.
DR. LYDIA GRAY: OK. Horses-- it could take like, seven, 10, 14 days before you start to see it. And what you'll see is when it's quiet and they're feeling comfortable and safe, they'll buckle their knee and collapse, and maybe fall. And people go, "Oh, he's narcoleptic." Ah, it's probably not. It's probably sleep deprivation, and what you're seeing is a sleep attack.
DAN: A sleep attack?
DR. LYDIA GRAY: A sleep attack. It's kind of an aggressive word for when things are calm, they just are like, "I'll just fall asleep." Sleep comes on them, and they can't help it.
DAN: And that's from consistently having poor sleep habits, not, for example, one bad night.
DR. LYDIA GRAY: Yeah, for example Dr. Joe Bertone is who I consider to be expert on horse sleep habits-- and he shares this story of a 4-H horse, pony that went to the county fairgrounds for their July, August county fair, and after a couple days, began to have these sleep attacks.
Well, they didn't know what was going on, so they called the vet. They're like, "Oh, something is terribly wrong. He's got some neurologic problem," right?
And one of the questions he asked-- a couple of questions he asked-- have you seen this horse roll lately? Or have you seen shavings on his back? So we'll get to that in a minute. Has anything changed in its social dynamics, like in the herd? And then how is the environment noise-wise? Are there any new disturbances?
Well, it turns out this poor horse was getting worked during the day and not having a normal routine-- well, like show in the morning, and show in the afternoon, and braiding, and bathing, and all that. And then at night, every night at 10 o'clock, they had fireworks.
And then at showgrounds, they'll leave the lights on in the barn all night long. He hadn't slept since he had been there, and it was just catching up with him. And they said when they got home, he slept for like two days straight flat-out, and then was his normal self again.
DAN: It's actually so funny they mention that. So for the showgrounds, is like keeping the lights on all the time-- I think people forget that. And one of our sponsor riders, Deanna Searles, what she says-- because when they go to Congress-- and they're there for like a month. So what she does is she'll get like a fly mask, and she'll put on the horses at night to help block some of the light for them.
DR. LYDIA GRAY: And maybe even like ear pom-poms or something.
DAN: Poor guy-- the fireworks going off every night, working all day.
DR. LYDIA GRAY: Yeah. And then people come in like at 3:00 and 4:00 AM to braid. So they may have just laid down to sleep, and then the lights are on again.
DAN: Time to get your hair done.
DR. LYDIA GRAY: Shows are rough. What else? What other questions do you have? Sleep habits, unusual patterns.
DAN: How can you encourage better sleep habits?
DR. LYDIA GRAY: Oh, yeah, how to encourage-- so I wrote down, what's required for a horse to sleep? Horses need to feel comfortable that they can lay down flat out and sleep because they're susceptible then to a predator. And they cannot get up fast and take off. If they're sleeping standing up, just dozing, and not really sleeping-- deep sleep or REM, they can quickly go. But when they lay flat out they're pretty susceptible.
DAN: They're vulnerable. Yeah.
DR. LYDIA GRAY: Yeah. They're very vulnerable. So they require a guard horse. And mares are very good at this.
So if you notice-- this is your observation-- in a herd, there'll be some laying down and some standing, watching over them. And they take turns. But you'll never see the entire herd laying flat out because somebody has to be on guard for the predators.
DAN: The got to sign for times of who's on watch, who's sleeping. Yeah.
DR. LYDIA GRAY: Shifts. Exactly, exactly. So that's one thing. There's a story of a horse that was in a herd, and then he got purchased, and he was the only horse in a place.
Well, he's like, I'm not laying down. I'm the only one. Then they come, they're going to get me. So they got another horse, a mini, and then it was fine.
DAN: So the mini was his guard horse so he could take a nap.
DR. LYDIA GRAY: Mini was a guard horse. I know. So let's see. What else?
The environment-- we talked about it has to be not disruptive, and usual, and the same. If it's disruptive but the horse is used to it, then that's probably fine.
The big one is-- and this one is probably the one that gets missed the most-- the horse has to be able to get down and get back up. So if you have an older horse maybe or a horse that's unsound-- and that's why the question of, have you seen them roll lately, or have you seen shavings on their back-- if they're not getting down and getting up, they can't sleep.
DAN: Yeah. Well, because the older ones, they are maybe a little bit nervous if they do, they can't get back up.
DR. LYDIA GRAY: As quickly.
DAN: Yeah.
DR. LYDIA GRAY: Yeah. Or just they're so stiff that they're hocks, and stifles, and fetlocks, they don't bend anymore. You've seen horses lay down. They don't look tremendously agile. So these older horses-- they might have been fused hocks or something. They can't do it.
DAN: If you give them a bigger stall, will that help them a little bit?
DR. LYDIA GRAY: That'll help-- more bedding. There's research study that says, thicker bedding-- horses will sleep longer. So it's good.
But also, this is a time to call your vet because they could come out and diagnose an unsoundness maybe and then prescribe something that will give them some relief, and talk to you about, let's develop a plan that will help your horse feel comfortable overall.
DAN: That's awesome. These are some great tips there. And some I might take just for my own personal use.
Evidence-Based References
- Greening, Linda, and Sebastian McBride. “A Review of Equine Sleep: Implications for Equine Welfare.” Frontiers in veterinary science vol. 9 916737. 17 Aug. 2022, doi:10.3389/fvets.2022.916737
- Luz, Marina P. F., et al. “Feeding time and agonistic behavior in horses: influence of distance, proportion, and height of troughs.” Journal of Equine Veterinary Science, vol. 35, no. 10, Oct. 2015, pp. 843-848.e1. https://doi.org/10.1016/j.jevs.2015.08.004.
- Greening, Linda, et al. “The Effect of Altering Routine Husbandry Factors on Sleep Duration and Memory Consolidation in the Horse.” Applied Animal Behaviour Science, vol. 236, Mar. 2021, p. 105229. https://doi.org/10.1016/j.applanim.2021.105229.